Actuating unit for speakers



Oct. 15, 1929 N. M. MICHAILOVSKY 1,732,204

wwnmunm FOR SPEAKERS Filed Aug. 23. 1928 paces a. 15, 1929 UNITED STATES PATENT OFFICE NICHOLAS M. MICHAILOVSKY, 0F BRONX, NEW "'YORK, ASSIGNOR, BY DIRECT AND MESNE ASSIGNMENTS, OF THIRTY-SEVEN AND ONE-HALF PER CENT TO PAUL NOEL BITTER, OF DOUGLAS MANOR, LONG ISLAND, NEW YORK, AND TWENTY-FIVE PER CENT TO HENRY W. BOETTGER, OF NEW YORK, N, Y.

ACTUATING UNIT FOR SPEAKERS Application filed August 2a, 1928. Serial No. 301,524.

Special objects of the present invention are to provide a motor or so-called' unit toractuating a speaker or other sound reproducing means, which will be highly sensitive, but at teristics will be of simple, sturdy, practical construction, easily assembled and inexpensive to manufacture.

a The foregoing and other desirable objects are attained by certain novel features of construction, combination and relations of parts curved arcs 20 of the pole pieces and of a length substantially equal to the reduced end portions 21 of the pole pieces. The width of these arcuate armature sections is shown as slightly greater than the width of the magnetic gaps 12, 13, so as toform complete spaced magnetic bridges across the gaps, in the neutral or balanced position of the armature. Beyond the arcuate portions the armature is shown as havin narrow ribs 22-bridging the magnetic gaps but operating freely in slots 23 formed in the end edges of the pole pieces.

This construction, it will be evident, provides a strong magnetic interaction between as illustrated in the accompanying drawing, the'armature and pole pieces which is as wherein one of the practical commercial embodiments of the invention is shown. It

' should be'understood, however, that as such illustration is particularly for purposes of disclosure, the structure may be modified as 5 Fig.- 1 is a broken sideelevation of one of v the units; Fig. 2 is a broken end view of the same; Fig. 3 is a detached perspective view of the armature element of the unit.

The field magnet, the yoke of which is in- 36 dicated at 5 may .be of the permanent or of the electromagnetic type, or a combination of 'both, such as illustrated wheremagnetcoils 6,7 on the legs of the yoke add their strength to the field produced by the permanent mag- 5 net yoke. The pole pieces 8 and 9 attached to the side faces of the yoke ends by screws 10, 1-1 carry the magnetic flux to the gaps 12,

13 at opposite sides of the yoke. These gaps v are indicated as relatively wide, for devices of.

. this general type, this being so particularly because of the novel formof the armature and 'polar structure.

The armature is shown in the present illustration'of the invention as a straight bar 14 of magnetic material pivotally supported mid- 7 length at 15 on a pin 16 carried by a nonmagnetic bridge 17 secured to the ends of the yoke byscrews 18. Adjacent its ends, this armature bar has arcuate wings 19 curved to operate freely within the correspondingly strong or stronger starting in the neutral position than in the positions of maximum movement, making the armature sensitive to minor impulses, suchas may be lost in a less sensitive instrument. The transmission element, by which the action of thearmature is imparted to the cone, diaphragm, or other reproducing element is shown as a rod 24 connected to-oneextreme end ofthe armature, but the form and place of-connection naturally may be varied to suit different requirements.

\ The armature is polarized in the-present disclosure by two flat magnetizing coils 25, 26

surrounding the end portions of the armature and indicated as held in position against the inside cheeks of the pole pieces by the nonmagnetic bridge 17 which is cut out on its opposite edges at 27 to accommodate said cm s.-

The magnetizing, efiects are furtherincreased' in the present disclosure'by provid ing supplementary magnetizing coils 28, 29 and 30, 31 on the pole pieces 8-8 and 9-9, these being connected up in series relation with each other and with the armature magnetizing coils 25, 26 as shown by the several connections 32 in such order that the actuating currents which are fed intothe instrument, such as the pulsating output current pole pieces in cooperating relation therewith. It has been found that the comparatively slight extra resistance introduced by these supplementary field coils does not inj u'riously these coils are at right angles to the armature magnetizing coils, injurious inductive coup:

ling between the coils may be positively pro- Vided against by placing conductive shields of copper or the-like betweenthe supplemental field coils and the armature coils. These shields are shown as engaged by the shouldered portions 34 of the bridge piece 17 whereby they and the coils which they protect are held in fixed position on the pole pieces, the coils en aging at the back against the inner faces-o the magnet arms. The main field coils 6, 7 are shown held in position onthe magnet arms by the supplemental field coils. An interlocking construction is thus provided between the several coils, pole x pieces, bridge and'shields by which all are interlocked in properly assembled relation by simply putting the parts togethe solid construction, and it will be obvious that other changes of more or less like nature may be made, all within the scope of the invention. In considering the operation, it should be noted particularly that by reason of the novel armature and polar construction and energizing coils, a maximum power ful starting impulse of the-armature is ob-' tained and that because of the magnetic interlinkage'between the armature ends and pole tips," this powerful action is continued throughout the range of armature movement.

Hence, the device is both sensitive and power ful throughout the range of action.

To prevent twisting of the armature out of the plane of the slots or notches in the pole pieces, the pivot pin or member 16 may be supported at both ends as indicated in Fig.

1, where the bridge 17 is shown as having a spaced overstanding portion providing an upper. bearing for the pin. If desired, the power transmission connection may be taken ofi from a point on the armature be tween the intermediate mounting and the extreme end of the same instead of from the exert a certain leverage power on the transmission connectlon. Instead of being bipolar the magnet structure may be of the single pole type. Other changes in structure mounted to operate across said gap and having a portion operating freely in the notches L of the pole pieces, a transmission element effect the operation of the armature and while opposite fac'esof the yoke, the adjacent ends The magnet yoke may be of laminated or in, an armature mounted intermediate the for said poles connected in series relation with end as shown so as to enable the armature to connected with said armature, means for magnetizing said armature, the portion of the armature which operates across the gap being of arcuate shape and the pole pieces having arcuate portions opposed to said arcuate portion of the armature.

.2. A driving unit for loud speakers or the like, comprising a magnet yoke having polar extensions providing magnetic gaps at'the of opposing pole pieces having notches therein, an armature mounted intermediate the gaps supported for movement in the direction of extentof said notches, said armature having bridging'portions operating across the gaps and narrow projecting ribs of less width and operating freely in the notches, a' transmission element connected with said armature and means for magnetizing the armature.

3. A driving unit for loud speakers or the like, comprising a magnet yoke having polar extensions providing magnetic gaps at the opposite faces of the yoke, the adjacent ends of opposing pole pieces having notches theregaps having bridging portions operating across the gap and projecting ribs operating freely in the notches, a transmission element connected with said armature, means for magnetizing the armature, said bridging portions of the armature being of arcuate formation and operating within the polar tips and said polar tips being "of corresponding arcuate shape. I

' 4. A drivingunit for loud speakers or the like, comprising a magnet structure having opposed poles, an. armature mounted in cooperative relation to said poles, a magnetizing coil for said armature and magnetizing coils said armature magnetizing coil.

5. A driving-unit for loud-speakers or like, comprising a magnet structure having opposed poles, an armature mounted." in co:- operative relation to said poles, a magnetizing coil for said armature, magnetizing coils for said poles connected in series relation with said armature magnetizing coil and means on said magnet structure for shielding said polar coils from said armature magnetizing coils.

6. A driving unit for loud speakersor the like, comprising a magnet yoke having polar projections at the opposite faces of-the same, polar magnetizing coils on said projections, armature magnetizing coils connected in series with said polar magnetizing coils'and an armature mounted in magnetizable relation to said armature magnetizing coils and in cooperative magnetic relation to. the polar projections.

7 A driving'unit for loud speakers or the like, comprising a magnet yoke having polar projections at the oppositefaces of the same, 130

polar magnetizing coils on said projections, armature magnetizing coils connected with said polar magnetizing coils, an armature mounted in magnetizable relation to said armature magnetizing coils .and in cooperative magnetic relation to the polar projections and'shielding means interposed between said polar coils and said armature coils.

8. A construction as in claim 7, in which a'common support for thecoils, armature and shields'is provided and is attached to the magne tie structure.

9. A driving unit for loud speakers or the like, comprising a magnetstructure having a polar projection, a movable armature mounted in cooperative relation thereto, a power transmission element connected with said armature, a magnetizing coil for the polar projection and a magnetizing coil for the armature connected in series relation with said polar coil.

10. A driving unit for loud speakers or the like, comprising a magnet structure having a polar projection, a movable armature armature connected in series relation with said "polar coil \and a separately energized magnetizing coil for the magnet.

12. A driving unit forloud speakers or the like, comprising a permanent magnet, a coil for increasing the normal magnetic force of said permanent magnet, an armature associated with said magnet, a magnetizing coil for said armature and a supplementary magnetizing coil for the magnet connected in phzise relation with the armature magnetizing coi 13. A construction as in claim 12, with shielding means on the magnet structure interposed between said supplementary and armature magnetizing coils. i

14. In apparatus ofthe character disclosed, a magnet/yoke, pole pieces secured to the opposite faces of said magnet yoke, a non-mag; netic bridge piece secured to the ends of said magnet yokes, an armature mounted on said bridge in cooperative relation to the pole pieces and magnetizing coils for the armature positioned by said bridge piece against the inner faces of the pole pieces.

, 15. A construction as in claim 14, with magnetizing coils for the pole pieces held in position thereon by said bridge piece.

v 16. A construction as in claim 14, with magnetizing coils on the pole pieces and shields for said coils'held in position thereagainst by said bridge piece.

17 In apparatus of the character disclosed,

an armature bar having arcuate wings at the opposite ends of the same and ribs projecting from said wings, a magnet structure having arcuate pole pieces opposed to the arcuate wings of the armature and notched to freely receive the projecting ribs and a power transmission element connected with said armature.

18. A driving unitfor loud speakers or the like, comprising a magnet structure having opposed poles, a vibrating member, a coil for said vibrating member and a magnetizing coil for the magnet structure connected with said first coil, whereby the same current impulses are present in both the magnetizing coil and the coil for the vibrating member.

19. A driving unit for loud speakers or' the like, comprising a magnet structure having opposed poles, a vibrating member, a coil for said vibrating member, a magnetizing .eoil for the magnet structure connected with said first coil,'whereby the same current impulses are present in both the magnetizing coil and the coil for the vibrating member, the said vibrating member coil and magnetizing coil being angularly arranged to avoid objectionable inductive coupling between the coils.

20. A driving unit for loud speakers or the like, comprising a magnet structure having opposed poles,-a vibrating member, a coil for said vibrating member, a magnetizing coil for the magnet structure connected with said first coil, whereby the same current impulsesare present in both the magnetizing coil and the coil for the vibrating member and conductive shielding means interposed between the field magnet coil and vibrating member coil. f 21. A driving unit for loud speakers or the like, comprising a magnet structure having opposed poles, a magnetic armature member interposed betweensaid opposed poles, a coil surrounding said armature for polarizing the same and a coil for magnetizing the magnet structure disposed at an angle to the armature polarizing coil and electrically connected therewith, whereby the same current impulses are present in both the polarizing and magnetizing coils.

In testimony whereof I aflix my signature.

- NICHOLAS M. MIOHAILOVSKY. 

